Effect of Mucuna bracteata leaf meal diet on growth, digestion and metabolism in Cyprinus carpio (Linnaeus 1758)

Abstract

 The current study evaluated mucuna leaf meal (MLM) as an alternative for de-oiled rice bran (DORB) in the Cyprinus carpio fingerling diet. Following a complete randomised design, a 60-day feeding experiment was carried out, where four isonitrogenous (32% crude protein) and iso-caloric (356 kcal DE 100 g-1) diets were prepared to constitute the following treatments; C (30% DORB, 0% MLM), T1 (20% DORB, 10% MLM), T2 (10% DORB, 20% MLM) and T3 (0% DORB, 30% MLM). Significant differences (p<0.05) were observed among treatments in terms of weight gain percentage (WG), protein efficiency ratio (PER) and specific growth rate (SGR). The growth performance of C. carpio fingerlings in the 30% MLM group (T3) was comparable to that of the control group (C, 30% DORB). Notably, fish fed with T2 diets exhibited better growth compared to those in other treatments. Digestive enzyme activities remained largely unchanged, except for amylase activity, which showed a significant increase in the T2 group. Additionally, alanine aminotransferase (ALT) activity in both muscle and liver was significantly elevated (p<0.05) in this group. These findings indicate that MLM can serve as an effective alternative to DORB in the diet without causing adverse effects, with the 20% MLM diet providing optimal growth and physiological benefits. However, malate dehydrogenase (MDH) and lactate dehydrogenase (LDH) activities  on hepatic and muscular tissues were significantly higher (p<0.05) in 30% MLM groups. Based on this, it can be concluded that the MLM can fully replace DORB (30%) without generating any detrimental consequences in the diet of C. carpio.

Keywords: Common carp, De-oiled rice bran, Digestibility coefficient, Lactate dehydrogenase, Malate dehydrogenase, Protein efficiency ratio, Specific growth rate